Overcenter buckles are commonly employed with tensioning straps used in cargo hold-down systems to produce a relatively high tension in the straps to prevent the cargo from shifting during transport. Such overcenter buckles usually consist of a handle pivotally mounted upon a body, and the strap is looped through the handle wherein pivoting thereof between open and closed positions tensions the strap. A latch assembly is usually mounted upon the handle having movement therewith and cooperates with catch portions defined upon the body when the handle is pivoted to the strap tensioning position for maintaining the handle in the closed position. Typical examples of such types of overcenter buckles are shown in U.S. Pat. No. 3,866,272 and the assignee's U.S. Pat. No. 4,464,811.
As apparent from the above patents, the buckle assembly is readily operable, easy to assemble and relatively inexpensive to manufacture. However, the fact that the latch assembly is located on the handle and has movement therewith requires the operator's fingers to be placed in close proximity of the pivot path of the handle when releasing the buckle which is undesirable as often the buckles are under high tension and releasing the handle from the closed tension position causes the handle to rapidly open possibly resulting in serious injury to the operator.
It is a object of the invention to provide an overcenter buckle having a body and a handle pivotally mounted thereon displaceable between closed and open positions wherein the buckle is readily operable, economical to manufacture and includes a latch assembly mounted on the body having a portion remotely located from the pivot path of the handle to facilitate release of the handle from the closed position under high tension conditions without the likelihood of causing serious injury to the operator.
It is a further object of the invention to provide an overcenter buckle incorporating an improved latch assembly wherein the latch assembly includes a lock plate slidably mounted on the body that is of an economical stamped construction and may be easily assembled to the body, yet is dependable under high tension conditions even after long periods of extensive usage.
In the practice of the invention a buckle includes a U-shaped body having parallel outstanding leg portions interconnected by a base. A pivot pin extends between the body sides near one end of the body whereon a handle, also having a U-shaped configuration, is pivotally mounted at one end thereon positionable between a closed tension producing position and an open tension release position. The handle includes strap receiving openings through which the tension strap is threaded and upon the handle being pivoted to the strap tension position the strap is pulled about the pivot pin tending to shorten the strap and produce a tension therein. The free end of the handle, opposite to that of the pivotally mounted end, terminates in the central portion of the body when the handle is in the strap tension position.
The body sides include a slot wherein an elongated lock plate is slidably received displaceable between a lock position and a release position, and the plate is normally biased to the lock position by a spring. The lock plate consist of a generally flat portion having an upturned outer end, and the flat portion includes a pair of parallel edges each provided with a recess defining a pair of parallel spaced legs. The legs are received in the body slots in the central portion of the body and the outer end is located at one end of the body remotely spaced from the pivot path of the handle.
The handle sides are provided with locking notches defining an abutment edge which cooperates with the lock plate upon pivoting of the handle to its closed tensioning position whereby the abutment edges pass through the recesses and form an abutting relation with the underside of the legs to releasably lock the handle in the closed position. Opening of the handle is readily accomplished by displacing the lock plate to the release position by either engaging and displacing the plate outer end with the finger or by lifting upwardly on the strap which abuts against the curved end whereby the recesses align with the locking notches abutment edges permitting the handle to be pivoted to its open position.
The lock plate is of economical construction formed by stamped and bending processes, yet, is durable under high tension loading conditions. Also, the fact that the lock plate is located on the body and positioned so that the upturned outer end upon which the actuating force is applied is remotely spaced from the path of the pivoting handle permits the buckle to be safely released under high tension conditions reducing the likelihood of causing serious injury to the operator.